Relaxation-Function-Dependent Two-Barrier Model for Nanoconfinement Effects on the Glass Transition

ORAL

Abstract

One of the central challenges in the study of nanoconfined systems has been the fact that distinct measures of these systems can report quantitative and qualitative differences in perturbations from bulk. This scenario has been further complicated by the recent observation in experiment of an apparent onset condition of nanoconfinement effects at temperatures only modestly above Tg. This observation has raised additional questions regarding the interpretation of large observed nanoconfinement effects in simulated systems at temperatures relatively much further above Tg. Here, using simulations and scaling theory, we show that this rich phenomenology can be unified via the combination of a two-barrier model of the glass transition with a barrier-truncation scenario for nanoconfinement effects. We discuss strong implications of these results for the viability of existing theories of the glass transition.

*This material is based upon work supported by the National Science Foundation under Grant No. CBET 1705738. The authors acknowledge the W. M. Keck Foundation for generous support enabling development of simulation methodologies employed in this work.

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Presenters

  • David Simmons

    • Department of Chemical and Biomedical Engineering, University of South Florida
    • Chemical and Biomedical Engineering, University of South Florida

Authors

  • David Simmons

    • Department of Chemical and Biomedical Engineering, University of South Florida
    • Chemical and Biomedical Engineering, University of South Florida

  • Daniel Mauricio Diaz Vela

    • Chemical and Biomedical Engineering, University of South Florida
    • Polymer Engineering, The University of Akron